1. Field of the Invention
The present invention relates to structural mounting components of the type which are embedded in cast concrete and, more particularly, to an overhead anchoring track which is designed to be embedded in a concrete ceiling member, for example.
2. Description of the Prior Art
Various overhead anchoring tracks of the type mentioned above are known from the prior art. These anchoring tracks normally consist of a C-shaped channel of rolled, bent or extruded metal with a plurality of anchoring members extending outwardly from the web portion of the channel. The channel profile includes short oppositely oriented leg portions on its open side, for engagement by the head of a suspension bolt of some other suspension member of a T-shaped outline.
The channel and the anchoring members are intended to be embedded in concrete in such a way that the open side of the channel faces away from the concrete member and the surface of the concrete member is flush with the outer side of the leg portions of the channel.
One such anchoring track is disclosed in the German Patent No. 26 31 396. This anchoring track uses anchoring members which have the form of short length portions of a rolled or extruded I-shape. One of the two flange portions of the I-shape is attached to a rectangular opening in the web portion of the channel, while the distal flange portion provides the anchoring engagement with the surrounding con- crete.
The rectangular openings in the channel web portion and the web of the I-shape are oriented in the longitudinal direction of the channel. The attached flange portion of the anchoring member includes a central protrusion which forms a head on the inner side of the channel. This head is formed from an upstanding central blade on the flange portion which, after insertion through the rectangular opening, is upset into a head shape in a riveting operation.
In an alternative mode of attachment, the rectangular opening in the web portion of the channel is wide enough to allow for the distal flange portion of the anchoring member to be introduced therethrough from the inside of the channel, while the attached flange portion is larger, so as to engage the web portion with lateral shoulders. An enlarged base portion of the I-shape near its attached flange is wide enough to fill out the rectangular opening and, being upset in a swaging operation, bulges laterally to attach the anchoring member to the web portion of the channel.
Among the shortcomings of this prior art solution are its cost, inasmuch as the anchoring elements are sawed-off or sheared off length portions of a specially shaped rolled or extruded I-shape, the rectangular openings in the channel require a special piercing and forming die, and the final attachment operation calls for an upsetting operation involving special tools and elevated forces.
As different sizes of anchoring tracks are needed for different applications, this means that a corresponding number of different sets of special tools and special I-shapes are required. A reduction in the number of different sizes of I-shapes can only be achieved by attaching oversized anchoring elements to some of the channel sizes.
The anchoring elements of this prior art solution are not adaptable to special requirements, such as reduced embedded depth. When it is necessary to connect the anchoring elements to other concrete reinforcing elements, such a load distributor plates, reinforcing rods, and the like, this can only be accomplished by welding special connecting members to the I-shapes.
Another prior art anchoring track is disclosed in the German Offenlegungsschrift (Published Application) No. 26 19 182. This publication teaches the use of regular head screws as part of the anchoring members, whereby nuts are welded to the outer side of the web portion of the channel, and the threaded shaft portion of each head screw engages the thread of one of the welded nuts.
In cases where the heads of these screws are not large enough to provide the necessary anchoring engagement with the surrounding concrete, load distributing plates or cross members must be welded to the screw heads.
This solution, while using inexpensive fasteners as anchoring members, requires a welding operation on the channel with entails the risk of distortion of the channel shape and the need for verification and/or corrective machining opera- tions.
Since the load-bearing connections between the anchoring elements and the anchoring track are constituted by the welds between the nuts and the web portion of the channel, these welds need to be verified carefully and machined, if necessary, thereby further increasing manufacturing costs.